Apparatus for refrigeration systems



Dec. 12, 1944. w. A. SISSON 2,364,669

APPARATUS FOR REFRIGERATION SYSTEMS Fi1ed June 7, 1941 WILLIAM A. SI's'sON ATTORN JMJMJ W Patented Dec.12, 1944 APPARATUS FOR- REFRIGERATION SYSTEMS William Albert Sisson, Elizabeth, N. J., assignor, by mesne assignments, to Cold Control, Inc.,'a

corporation of Delaware Application June 7, 1941, Serial No. 396,982

.6 Claims.

This invention relates to a refrigeration system for refrigerating having general applicability, but particularly intended for the cooling of railroad refrigerator cars which are ordinarily cooled by means of ice. Ice is considerably bulkier than dry ice when compared upon the basis of refrigerating capabilities per unit; weight of each refrigerant. With dry ice, however, because of its exceedingly low temperature, it is diiiicult to regulatethe temperature of the refrigerating enclosure to be cooled. The refrigeration system to be described herein enables dry ice to be used as a primary refrigerating medium, and hence increases the volumetric capacity of a freight car or refrigerating enclosure and permits sensitive regulation of the temperature therein. 7

It is an object of the invention to construct a new and novel refrigerating system which utilizes dry ice as a primary refrigerant and which maintains a relatively uniform temperature within the refrigerating enclosure.

Another object of the invention is to construct a refrigerating system which provides a storage means for a secondary refrigerant and also a thermostatically controlled valve which closes when the temperature ,in the refrigerating eniclosure is at a desired point, whereupon secondary refrigerant is drawn out of at least the evaporator and condenser of the refrigerating system into the storage means. 7

Other objects of the invention will be more apparent from the following description taken in connection with the accompanying drawing, illustrating a preferred embodiment of the invention, in which:

Figure 1 is an elevational view, of the refrigerating system showing a storage housing or bin for dry ice, a condenser therein and associated parts thereof in section.

Figure 2 is a section, taken on line 2-2 of Figure .1, through the storage bin and condenser for the dry ice or primary refrigerant and also shows the storage means for the secondary refrigerant.

The refrigerating system includes an insulated housing or bin Ill within which there is a; condenser I I. The condenser preferably forms a, lining for the insulated housing I, although any disposition of the condenser therewithin is contemplated. The insulated housing may have a lid or cover I 2 which may be removed for the insertion of dry ice within'the housing and the condenser. The condenser has a well for the condenser, and consequently thesecond- I73 at thebotf tom thereof which providesthe lowermost point ary refrigerant therewithin normally flows or drains to this point.

The well it of the condenser M is connected by means of a pipe it to an evaporator at. The evaporator may be of any suitable form, although the plate coil type is preferred. The top of the evaporator l5 and the top of the condenser H are connected by means of an open pipe it. The evaporator is'located in the enclosure to be refrigerated, such as the interior of a freight car or other structure, which is to contain perishables. It is also above the level of the well it so that the liquid refrigerant will flow from the evaporator into the well when the level of the liquid refrigerant is loweredor the refrigerant is removed from the condenser as will appear more fully hereinafter.

The secondary refrigerant is poured intothe refrigerating system and it flows to both the condenser and evaporator through the connecting pipe H. The secondary refrigerant is one which evaporates below the temperature at which the refrigerating enclosure is desired to be kept and which liquefies well above the temperature of the primary refrigerant or dry ice. Such secondary refrigerants include Freon, such as dichloro- 'difiuoromethane, or methyl chloride, etc. Normally the secondary refrigerant circulates from the condenser to, the evaporator as a liquid, evaporates in the latter into its gaseous form, and in so doing heat is absorbed from the walls of the evaporator. The gas passes off from the top of the evaporator through the pipe is to the condenser where the gases are cooled by the dry ice or other primary refrigerant therein, whereupon the gas is again condensed to a liquid and in due time flows again through the pipe M to the evaporator. By such continual circulation, the refrigerating enclosure, such as a freight car, is continually maintained cool and the contents thereof is not endangered by the possibility of being subjected to the extremely cold temperaturesof dry ice. I

. A secondary refrigerant storage means, which has sufilcient capacity to hold all of the liquid secondary refrigerant,'is provided in the chambers I'lv located within the condenser ll, These storage chambers are connected together such as by 91988 [8 at each end thereof. The storage chambers I! are connected to the refrigerating system at its lowermost point which may be at any suitable part, such as the condenser, evaporator orthe liquid connection ll. The connection particularly illustrated is by means of a pipe Is to the well I: of the The storage means l1 need not be a, plurality of chambers, and this form is illustrated merely because it is desirable to have a maximum surface therefor for exposure to the dry ice or the atmosphere within the insulated housing. The top of the vstorage means I1 is connected by means of a pipe III to the top of the evaporator IS. A thermostatically controlled valve 2| is included in this pipe connection. The thermostatic element 22 is located in the refrigerating enclosure so that the valve is controlled by the temperature therein.

The normal operation of the refrigerating system has been described, during which time the evaporator is cooling the refrigerating enclosure. Some gaseous flow occurs through the connection 20 in the same manner that flow takes place through the connection Hi. When the temperature in the refrigerating enclosure has reached the desired degree of coolness, the thermostatic element operates to close the valve 2i. When this occurs, the flow of gaseous secondary refrigerant through the pipe 20 ceases, whereupon the gaseous refrigerant in the storage chambers l1 condenses and creates a vacuum pressure therein. Since the evaporator and condenser contain ,a gas above the liquid therein and said gas is at the pressure of evaporation liquid refrigerant is sucked or forced therefrom into the storage chamber I! through the pipe Hi from both the evaporator and the condenser. Since the amount of liquid refrigerant in the evaporator l5 has been reduced, evaporation therein proportionately ceases and consequently halts the rate of further cooling of the refrigerating enclosure. Similarly, condensation of gaseous refrigerant in the condenser is proportionately reduced. This method of operating a refrigerating system removes liquid secondary refrigerant from the condenser where the condensing step takes place and from the evaporator where the evaporating step takes place.

By way of further explanation of the operation of my invention, it may be said that if a railway car, for instance, is under refrigeration and it is required to travel from a comparatively warm region to and remain in, or pass through,

for a considerable time, a. cold region in which there will be no leakage of external heat through the car walls, such for example as during the winter time when the outside temperature drops to 5 F. and it is desired to maintain a temperature inside of the car of 20 F., a substantial part of the liquid will eventually be withdrawn from both the evaporator l5 and condenser II and stored during that period in the chambers l1.

When the temperature in the refrigerating enclosure increases to such a point that the thermostatic element 22 again opens the valve 2|, the gaseous pressure in the evaporator flows through the pipe 20 to the storage chambers l1, and the liquid refrigerant therein flows out into the condenser and evaporator. The liquid refrigerant now being again present in the evaporator, it evaporates and creates its cooling effeet in the manner described hereinbefore.

This invention is presented to fill a need for improvements in a method and apparatus for refrigeration systems. It is understood that various modifications in structure, as well as changes in mode of operation, assembly, and manner of use, may and often do occur to those skilled in the art, especially after benefiting from the teachings of an invention. Hence, it will be understood that this disclosure is illustrative of preferred means of embodying the invention in useful form by explaining the construction, operation and advantages thereof.

What is claimed is;

1. A refrigerating system comprising insulated condenser means to hold a primary refrigerant, evaporator means external thereof. a connection between the bottom of the condenser means and the evaporator means for liquid flow therebetween, a connection between the top of the evaporator means and the condenser means for gaseous flow therebetween, a secondary refrigerant in the condenser means and evaporator means, a storage means within the insulated condenser means and connected with one of the aforesaid means adjacent the bottom thereof, a connection from the top of the storage means to the top of the evaporator means, and a thermostatically controlled valve in the last mentioned connection means which draws liquid refrigerant into the.

storage means from the condenser and evaporator.

2. A refrigerating system comprising an insulated bin to hold a primary refrigerant, condenser means in the insulated bin, evaporator means external thereof, a connection between the bottom of the 'condenser means and the evaporator means, a connection between the top of the evaporator means and the condenser means, a secondary refrigerant in the condenser means and evaporator means, a storage means within the insulated bin and connected with one of the aforesaid means adjacent the bottom thereof, a connection from the top of the storage means to the top of the evaporator means, and a thermostatically controlled valve in the last mentioned connection whereby upon closing of the valve gaseous secondary refrigerant in the storage means is condensed and liquid refrigerant is drawn into the storage means.

3. A refrigerating systemcomprising an insulated bin to hold a primary refrigerant, a condenser in the insulated bin, an evaporator external thereof, a connection between the bottom of the condenser and the evaporator for normal liquid flow from the condenser to the evaporator, a connection between the top of the evaporator and the condenser for gaseous flow from the evaporator to the condenser; a secondary refrigerant in the condenser and evaporator, a storv tioned connection whereby upon closing of the valve gaseous secondar refrigerant'in the storage means is condensed and liquid refrigerant is drawn into the storage means.

4. A refrigerating system comprising an insulated bin to hold a primary refrigerant, condenser means forming a lining for the insulated bin, evaporator means external thereof, a connection between the bottom of the condenser means and the evaporator means for liquid flow from the former to the latter, a connection between the top of the evaporator means and the condenser means for gaseous flow. from the former to the latter, a secondary refrigerant in the condenser means and evaporator means, a storage means within the insulated bln and connected with one of the aforesaid means adjacent the denser within the bottom thereof, a connection from the top of the storage means to the top of the evaporator means, and a thermostatically controlled valve in the last mentioned connection whereby upon closing of the valve gaseous secondary reirigerant is condensed in the storage means and liquid refrigerant is drawn into the storage means.

5. A refrigerating system comprising an insulated bin to hold insulated bin, a well at the bottom of the condenser, an evaporator external of the insulated bin. a connection between the bottom of the condenser and the evaporator for normal liquid flow from the condenser to the evaporator, a connection between the top of the evaporator and the condenser for gaseous flow from the evaporator. to the condenser, a secondary refrigerant in the condenser and evaporator, a storage means within the insulated bin and condenser and located centrally thereof, the bottom or the storage means being connected with the well of the condenser, a connection from the top of the storage means to the top of the evaporator, and a thermostatically controlled valve in the last mentioned connection adapted to be controlled by the temperature in a refrigerating enclosure containing the evaporator whereby upon ciosing of the valve gaseous secondary a primary refrigerant, a conthereof, the

refrigerant in the storage means is condensed evaporator for normal liquid flow from the condenser to the evaporator, a connection between the top of the evaporator and the condenser for gaseous flow from the evaporator to the condenser, a secondary refrigerant in th condenser and evaporator, a storage means within the insulated binand condenser and located centrally bottom of the storage means being connected with the well of the condenser, a. connection from the top of the storage means to the top of the evaporator, and a thermostatically controlled valve in the last mentioned connec tion adapted to be controlled by the temperature in a refrigerating enclosure containing the evap= orator whereby upon closing of the valve gaseous secondary refrigerant in the. storage means is condensed and liquid refrigerant in the condenser and evaporator is drawn into the storage means.

ALBERT SISSON. 

